Among the modular rotary tools, it is possible to distinguish between two different types. In a first type, as can be seen, for example, in WO 2008/072840 A2, the torque faces extend radially outward up to an outermost periphery of the cutting head, also referred to as the drill bit bit body clearance. According to a second variant, the torque faces are formed directly on the coupling pin as lateral surfaces thereof that cooperate with corresponding inner lateral surfaces of the fastening segments.
Both the torque faces and the clamping faces of the cutting head as well as those of the carrier are located across from each other in pairs when in a coupled state, i.e. when the cutting head is inserted into the carrier.
For axial pull-out protection, approximately horizontally-extending stop faces are often formed on the coupling pin that cooperate with corresponding stop faces of the carrier to ensure form-fit securing in the axial direction for the cutting head. This form-fit securing prevents the cutting head from being pulled out of the carrier in the axial direction, for example when pulling the rotary tool back out of the drilled hole after a drilling operation. In WO 2008/072840 A2, a circumferential groove in the form of a recess is formed in the coupling pin to form this axial pull-out protection.
JP 2016 193461 A discloses a further rotary tool of this type in which a clamping screw is provided in the carrier to clamp the cutting head. On each of the fastening segments, a lock that projects in the transverse direction is formed that engages into a recess in the coupling pin.